A restaurant down the road from his small facility fries them up in famously spicy Sichuan sauce for the gutsier eaters.

"People don't believe how good it is until they try some," Li told AFP, putting a live one into his mouth as others crawled all over the place and people visiting.

Known colloquially as American cockroaches, the Periplaneta americana is one of the largest species and are consumed for a variety of ailments: stomach ulcers, respiratory tract problems, and even simply as a tonic.

"The greatest effect of cockroaches are that they have great immunity, which is why humans will absorb its benefits after eating them," Li said, noting that in China cockroaches are dubbed "Little Strong" because they can live for days even after being cut in half.

Tucked at the edge of bamboo-covered mountains in Yibin, Li's facility is a nondescript single-storey former farmhouse surrounded by crop fields and livestock farms.

The breeding area is roughly the size of a badminton court, with windows sealed off with netting to prevent any great escapes.

Security is paramount: In 2013, some one million cockroaches escaped a farm in eastern Jiangsu province roamed free after their greenhouse was destroyed.

- Health benefits? -

Li's cockroaches live between the spaces of square wooden frames that are held together by pipes and stored in racks lining two rooms. The place is kept warm and humid, leaving a smell reminiscent of damp clothes.

Feeding time causes a frenzy -- as Li heaps a mix of ground corn, fruit and vegetable peelings on small trays, the insects suddenly swarm the platforms, crawling over each other.

"We breed them in a hygienic environment. They eat proper food -- nothing synthetic," he said.

Every three months, Li harvests the cockroaches to keep the population under control by dropping some into a vat of boiling water before dehydrating the carcasses.

Last year, he sold one tonne of dried cockroaches to a pharmaceutical factory for nearly 90,000 yuan ($13,500).

Li ran a mobile phone shop when he went into cockroach farming in 2016 because it was low cost business and the insects are easy to rear. He converted his farmhouse and bought eggs from another breeder.

His main source of income is from selling the insects directly to farms or medicine factories, and this is supplemented by an online shop his daughter helped set up. Half-a-kilo (1.1 pounds) of whole dehydrated insects retail for between 100 and 600 yuan ($15-$90).

In neighbouring Xichang, the Gooddoctor Pharmaceutical Group runs the world's largest cockroach farm where a whopping six billion insects held in a facility that employs artificial intelligence in monitoring movement and environmental conditions.

Cockroaches were added in the late 16th century to the Compendium of Materia Medica, the most comprehensive medical book ever written about traditional Chinese medicine.

The bugs have detoxifying properties and can act as a diuretic, said Liu Daoyuan, chief specialist at the Yinchuan City Yongshou Medical Centre.